Beam Angle

Beam angle is used to express the width of the light emitting from the source. The narrower the beam angle the more focused the light energy is. Comparing two 40 watt lights one with a beam angle of 30(a) and another with a beam angle of 90(b), They both produce the same amount of light output but (a) will appear brighter in the beam angle compared to (b) at the sacrifice of light spread.